To move from one energy<span> level to another, an </span>electron<span> must gain or lose just the right amount of </span>energy<span>. </span>Electrons are said to be quantized<span> because they need a quantum of </span>energy<span> to move to a different sublevel. ... When atoms absorb </span>energy<span>, </span>electrons<span> move into higher </span>energy<span> levels.</span>